Among the following, the incorrect statement is:

To decide which one of the four given statements is wrong, we recall first what a glycosidic linkage means. A glycosidic linkage is the covalent bond that joins two monosaccharide units after the elimination of a molecule of water. The bond is denoted as $$\alpha$$ or $$\beta$$ according to the configuration at the anomeric carbon, and the numbers indicate the carbon atoms of the two rings that are directly joined. For example, “$$\alpha$$-1,4” means the -O- bridge runs from the anomeric carbon-1 of the first sugar in the $$\alpha$$-configuration to carbon-4 of the second sugar.

Now we examine each statement one by one.

Statement A says: “cellulose and amylose has 1,4-glycosidic linkage.” Cellulose is a polymer of $$\beta$$-D-glucose units linked through $$\beta$$-1,4 bridges, i.e. $$\beta$$-D-Glc(1 → 4)$$\beta$$-D-Glc $$\dots$$. Amylose (the unbranched component of starch) is a polymer of $$\alpha$$-D-glucose units joined through $$\alpha$$-1,4 bridges, i.e. $$\alpha$$-D-Glc(1 → 4)$$\alpha$$-D-Glc $$\dots$$. Both indeed use a 1,4 linkage (only the $$\alpha/\beta$$ orientation differs). Hence Statement A is true.

Statement B says: “lactose contains $$\beta$$-D-galactose and $$\beta$$-D-glucose.” Lactose consists of one $$\beta$$-D-galactose and one $$\beta$$-D-glucose connected by a $$\beta$$-1,4 link from C-1 of galactose to C-4 of glucose. So the description is accurate. Therefore Statement B is true.

Statement C says: “maltose and lactose has 1,4-glycosidic linkage.” Maltose = $$\alpha$$-D-Glc(1 → 4)$$\alpha$$-D-Glc, clearly 1,4. Lactose, as just discussed, is $$\beta$$-D-Gal(1 → 4)$$\beta$$-D-Glc, also 1,4. So both indeed possess 1,4 linkages. Statement C is true.

Statement D says: “sucrose and amylose has 1,2-glycosidic linkage.” Sucrose is $$\alpha$$-D-Glc(1 → 2)$$\beta$$-D-Fru; it truly contains an $$\alpha$$,1 → 2,$$\beta$$ bridge, so the part about sucrose is right. Amylose, however, we already know is based on $$\alpha$$-1,4 linkages, not 1,2. Thus the claim that amylose has a 1,2 linkage is wrong. Because the statement lumps sucrose and amylose together and declares that both have 1,2 linkages, the whole statement becomes incorrect.

All the other three statements are correct, so the only incorrect one is Statement D.

Hence, the correct answer is Option D.